The CVD tube furnace uses a double shell structure and the furnace adopts alumina fiber material, which can heat the sample to 1700℃. The left flange is equipped a digital vacuum display meter, the right flange is equipped with a KF-25 interface, which can be connected to the mechanical pump (pumping speed of 226L/m). At the same time, the left flange is equipped with a sleeve joint of φ6.35so that the furnace body can be connected with the mixing system. The precise temperature control system provides 30 heating and cooling procedures, its’ temperature control accuracy is + / - 1 C.